As the technology of arrays of devices have developed, the metal-semiconductor of MESFET type of device has been found to be advantageous because of its packing density and simplicity of manufacture. The MESFET device employs a charge provided through a gate electrode to modulate current flow in a portion of the device called a channel between two electrodes known as source and drain electrodes. There are two types of such devices. An enhancement mode type of device wherein the charge on the gate electrode enhances the presence of carriers in the current conducting channel and the depletion mode type of device wherein the charge on the gate operates to deplete the current conducting channel of carriers. The enhancement mode device has essentially no current flow in the "off" condition whereas the depletion mode device has current flow in the "off" condition. In order to make arrays of such devices all devices are each made in an identical semiconductor region of the order of a thousand angstroms in thickness, with very precise electrode spacing. Such criteria have been difficult to achieve.